1. Field of the Invention
This invention relates to correction tape cassettes for typewriters for correcting mistyped characters, and more particularly concerns tape feed control apparatus for controlling the amount of correction tape being fed to a printing point for lifting-off or covering-up a typewritten character which was typed by mistake.
2. Description of the Prior Art for covering-up a character which has been typed onto a sheet of paper by mistake have been in use for some time. In a typewriter which is using a multi-strike ribbon cassette, a cover-up correction tape cassette is provided which covers-up the mistaken character. In a typewriter which is using a single-strike ribbon cassette, a lift-off correction tape is provided to lift-off the mistaken character.
U.S. Pat. No. 4,900,171 which issued on Feb. 13, 1990 to Mueller and Cappotto, discloses a prior art ribbon cassette and correction tape cassette, and this patent is incorporated herein by reference. This patent discloses means for assuring ink ribbon and correction tape compatibility in a device which utilizes a first cassette having an ink ribbon therein and second cassette having a correction tape therein including a switch means in the device that controls the on-off condition of the device, and means located on one of the cassettes which will activate the on-off switch only when the device contains an ink ribbon in the first cassette which is functionally compatible with the correction tape in the second cassette, such as, for example, functional compatibility between a single-strike ink ribbon and a lift-off correction tape, or functional compatibility between a multiple-strike ink ribbon and a cover-up correction tape.
U.S. Pat. No. 4,886,383, which issued on Dec. 12, 1989, to Mueller, is also incorporated herein by reference. This patent discloses a tape cassette which has a sensing arm pivotally mounted thereon biased against a correction tape on a take-up spool for sensing the amount of correction tape thereon, and a correction tape feed mechanism mounted in a typewriter which has a metering post for engaging the sensing arm at varying locations to cause the correction tape mechanism to feed the correction tape at substantially equal amounts regardless of the amount of correction tape on the take-up spool.